A conventional wafer level package (WLP) includes a device wafer having one or more devices disposed on a substrate that is bonded to a cap or lid wafer using bonding structures. The finished WLP forms a hermetically sealed interior to protect the devices and extend their useful life. Getters have historically been used to reduce the pressure within the sealed vacuum cavity of WLP, and to maintain the vacuum over the life of the device. A getter is typically a material that, when activated, captures gas molecules in a vacuum or low pressure environment. The getter absorbs, adsorbs, and/or physically entraps oxygen and other molecules and impurities that are outgassed from the components packaged within the WLP, and in certain instances, may also trap impurities that leak through the WLP from the external environment. The getter is typically made from materials that react with the impurities to form stable compounds, such as oxides, carbides, hydrides, and nitrides.
As die sizes shrink, the amount of space that can be allocated to the getter within the WLP is also reduced. During the wafer bonding process, there is thus an increased potential to contaminate these small getters. There is therefore a need for a method or system that can compensate for this loss in getter size and subsequent increase in the risk of contamination.